In the related art, an identity determining system using the image of a face has a problem of identity theft using, for example, a picture. In order to prevent the identity theft using the picture, it is necessary to determine whether the face input from, for example, a camera is a user's own face or a face that is present on a plane, such as a picture.
In order to meet the requirements, there is a conventional technique that detects the feature points of the face from an acquired image (data) and determines biometric identity on the basis of whether the movement information of the feature point during registration is identical to that during authentication. In addition, there is another technique that determines biometric identity on the basis of a change in an eye region or a mouth region.
However, a change in the movement of the feature point or a change in a local pattern has specifically only two-dimensional information. Therefore, although it can detect a planar change in the face in the image, it is generally difficult to determine whether or not the face has a three-dimensional shape. In addition, it is necessary to force the user to make an unnatural action, such as making a change in expression.
On the other hand, when a stereo camera is used to directly calculate the depth of an acquired image, it is possible to determine whether or not the face has a three-dimensional shape. However, in this case, a plurality of cameras or a special apparatus is needed, which makes applicable fields of the apparatus narrow.